Analysis of architecture and performance of three-dimensional braided composites

The design and fabrication of preforms for advanced composites have gained considerable attention in light of recently developed textile preforming techniques. It is within this realm of preforming technology that a full advantage of the knowledge to a process-structure-property relationship of three-dimensional (3D) braided composites may be realized. The fabrication history of these preforms directly determines composite microstructures and resulting mechanical properties. This chapter mainly reports the history of development, architecture, and processing techniques of 3D four-step braiding preforms and composite materials. The modeling strategy of three repeat unit cells (inner, surface, and corner repeat unit cell (RUC)) representing the entire braiding structure is presented along with corresponding structure characterization and mechanical properties of RUCs. Finally, the static, dynamic, and fatigue behaviors of 3D four-step composites under three-point bending, impact loading, and cyclic loading are reported.